1. Technical Field
The present invention relates to a mount structure, an electrooptic device, and an electronic device, and in particular, it relates to a mount structure in which terminal groups including multiple terminals are conductively connected to each other.
2. Related Art
Known electrooptic devices mounted to electronic devices such as portable phones, notebook computers, and TV sets have a structure including an electrooptic panel such as a liquid-crystal display panel and a flexible wiring board mounted to the electrooptic panel. When a driving circuit for driving the electrooptic panel is mounted to the panel, the flexible wiring board supplies display data and control signals sent from the display control system of the electronic device to the electrooptic panel. When the driving circuit is not mounted to the electrooptic panel, the driving circuit is mounted to the flexible wiring board or another circuit board to which a flexible wiring board is connected. In such cases, the flexible wiring board supplies a driving signal output from the driving circuit to the electrooptic panel.
The above structure is such that multiple input terminals are arrayed in a row along a rim of the electrooptic panel, while multiple connecting terminals are arrayed in a row along a rim of the flexible wiring board in correspondence with the input terminals. When the flexible wiring board is mounted to the electrooptic panel, the input terminal row and the connecting terminal row are opposed with an anisotropic conductive film (ACF) or the like in between, to which heat or pressure is applied with a tool to bring the corresponding input terminals and connecting terminals into conductive connection.
The connecting terminal row of the flexible wiring board is in exact correspondence with the input terminal row of the electrooptic panel. However, since the flexible wiring board is mainly formed of polyimide resin, it expands or contracts greatly because of temperature changes or moisture absorption, thus changing the terminal pitch of the connecting terminal row. This causes deviations in array pitch between the connecting terminal row and the input terminal row on the glass substrate that is little influenced by temperature changes or moisture absorption to bring the connecting terminals and the input terminals out of agreement with each other, thus causing mount failure.
Thus, there is proposed a terminal structure and a method for mounting in which the multiple input terminals and the multiple connecting terminals are arranged linearly along multiple lines that pass through common points arranged apart in a predetermined direction and intersecting the direction of the array of the input terminal row and the connecting terminal row so that even if the array pitch of the connecting terminal row changes to some extent because of the expansion or contraction of the flexible wiring board, the array pitches can be agreed to each other by relatively shifting the input terminal row and the connecting terminal row in the direction in which the distances from the common points change (e.g., refer to JP-A-2003-258027).
However, even the above structure in which the array pitch can be agreed by adjustment at packaging has the problem of disagreement between terminals, causing mount failure due to uneven expansion or contraction of the flexible wiring board.
Furthermore, it also has the problem of disagreement between terminals, causing mount failure due to variations in the pattern of the connecting terminals of the flexible wiring board (e.g., variations in the width of the connecting terminals).